| Basics of ColocationServer colocation is | | | | changes have been made to the LILO |
| usually for those who own their own server | | | | configuration remember to run "/sbin/lilo -v" |
| hardware and require complete control over | | | | and ensure there are no errors.Also make sure |
| the server configuration. Colocation | | | | the kernel "works" properly with the |
| specialists will house and connect a server | | | | hardware. This is especially true if have |
| you own, to a fast internet connection, | | | | compiled the kernel yourself or are using |
| usually in a secure datacentre, with 24/7 | | | | specialist hardware.Make sure the server |
| support.It is important to choose a | | | | "Auto Powers" onMost colocation facilities |
| colocation provider that either has their own | | | | provide an auto power cycler from a web |
| data center or has a presence in one of the | | | | interface. However this can fail if the |
| leading "data hotels." World Class data | | | | machine does not auto power back up |
| centres are located in major industrial | | | | (requiring the intervention of a techie). |
| cities (New York, London, Frankfurt for | | | | Most server BIOS's are equipped with either |
| example). Here they are able to take | | | | "OFF", "LAST STATE" or "ALWAYS ON". In this |
| advantage of the convergence of high capacity | | | | case you will require "ALWAYS ON." it is |
| network connectivity that occurs in a major | | | | possible to hack cheaper ATX motherboards to |
| commercial centre. For instance fibre, and | | | | be "ALWAYS ON" but it is better to consider a |
| metrolinks and ease of connection to major | | | | more expensive motherboard.Properly |
| Points of Presence (POPS) to the major | | | | Configured NetworkMake sure you configure the |
| telco's. For this reason only a very few of | | | | network addresses, DNS server and gateways |
| the leading ISP's or colocation specialist | | | | properly prior to delivery of the dedicated |
| operate their own dedicated centre's due to | | | | server. This information will have been |
| the costs of providing remote connectivity, | | | | provided in advance by the colocation |
| redundant power sources, air conditioning and | | | | provider. Also make sure you can get back |
| filtered clean air.Also not all internet | | | | into the server remotely by having the SSHD |
| connections are equal. You really need to | | | | daemon running (telnet is not secure).OpenSSH |
| enquire if your colocation specialist is | | | | is shipped with all the main Linux |
| "multihomed" using the BGP protocol by having | | | | distributions. You might wish to consider |
| at least two connections to Tier One | | | | configuring SSH (usually done in /etc/sshd |
| providers. Tier One providers are very large | | | | sshd_config) to work with Protocol2 only, |
| ISP's or Telco's who operate their own fibre | | | | disable root logins (or only allow public key |
| links and networks without having to operate | | | | exchanges with the `without-password` option) |
| traffic (or transit) over another ISP's | | | | and to turn off X11 forwarding as this is not |
| network. An example of a Tier One provider | | | | required on a production server.Many servers |
| would be Level3 communications.In addition to | | | | have multiple ethernet connectors, so it an |
| Tier One connections, the colocation | | | | be helpful, if you are not using the second |
| specialist should have peering arrangement's | | | | interface to either mask it off with tape or |
| at major exchange point's such as LINX. A | | | | label the correct ethernet device. |
| peering point is where a number of ISP's | | | | |
| arrange to "meet up" to exchange traffic | | | | Set up a Serial ConsoleThis is sometimes |
| between each other rather than pay for | | | | called "out of band" management. Quite often |
| transit over someone else's network. In a way | | | | a colocation provider will have a serial |
| they are "cutting out the middleman!" This | | | | terminal on site. This is basically a server |
| not only improves redundancy but also reduces | | | | itself but with loads of serial ports. This |
| latency; people will be able to access the | | | | enables you to connect to your server if the |
| websites and content hosted on your colocated | | | | network has failed to your server for any |
| server much faster if you colo host is well | | | | reason.The most common serial port settings |
| peered.Quite often a web host or Colocation | | | | are 9600 8n1 (we do not recommend running it |
| ISP will negotiate many peering arrangements | | | | a faster speed). If you are running a Red Hat |
| with other ISP's with whom they are | | | | Linux server serial console access is usually |
| exchanging a lot of traffic. Not only does | | | | configured in "/etc/inittab." Try inserting |
| this give them more resilience, but it also | | | | the line below:co:23456:respawn:/sbin/agetty |
| reduces their own transit costs with the Tier | | | | ttyS0 9600 vt100Cooling ConsiderationsServers |
| One providers enabling them to offer more | | | | run pretty hot mainly due to modern |
| competitive data transfer pricing.Latency is | | | | processors. Even in a fully air conditioned |
| particularly important when it comes to game | | | | environment. It will pay you look into |
| server hosting and colocation. Quite often an | | | | cooling. A lot will depend on rack density |
| ISP specialising in games hosting will give | | | | however this is one more reason why you |
| you an IP address for you to test ping times | | | | should consider a rack optimised server, as |
| and carry out traceroutes.Hardware | | | | the air cooling in a colocated environment |
| ChoicesServer housing costs in London or New | | | | should have been taken into consideration. |
| York can be expensive. Not suprisingly your | | | | You can also familiarise with the chipset |
| hardware should be "rack optimized." | | | | architecture of your motherboard and consider |
| Colocation is usually priced "per U." A "U" | | | | setting up "sensors." You can then monitor |
| is 1.75 inches (or 4.44 cms). So rack | | | | the temperature of your CPU and motherboard |
| servers, unlike desktop machines are long and | | | | and graph it using MRTG. |
| flat. Data Centre's also employ different | | | | |
| types Rack Cabinets which are typically 42U | | | | Cheap Colocation ProvidersWell apart from us |
| in height, enough to house 42 1U servers | | | | that is! However the following London based |
| though some of this space is used to | | | | colocation providers come highly recommended. |
| accomodate switches, cabling. Often some | | | | In other words, they are in demand, know what |
| space is left free to allow for efficient air | | | | they are doing and possess "clue."Bogons - - |
| distribution in the cabinet.It's often worth | | | | Based in Telehouse, but they may only usually |
| liasing with your colo specialists over the | | | | Sun Netra servers.Black Cat Networks - - |
| choice of the physical hardware and | | | | Based in Redbus Harbour Exchange.Jump |
| especially the case and rack mounting. The | | | | Networks - - Also based in Telehouse North, |
| colocation specialist will know which brands | | | | Docklands.Additional ThoughtsYou may wish to |
| work in their racks. Personally I have found | | | | consider disc or hard drive redundancy. |
| Dell Rack Optimized Servers and rail kits the | | | | Although the "MTF" or Mean Time to Failure" |
| quickest and easiest to rail up.So you have | | | | quoted by hard drive manufacturers is |
| decided on the hardware, and you are about to | | | | impressive, hard drive failure, especially |
| ship your server to the remote colocation | | | | IDE failure happens depressingly often. With |
| data centre. Bear in mind your server will | | | | advent of S-ATA drives there is really no |
| shortly be hundreds of miles away, indeed if | | | | excuse, expecially if your are on a budget. |
| you are in the USA, it might even be few | | | | You should consider cheap S-ATA drives (if |
| hours flight away so there are a few | | | | you cannot afford SCSI) with Linux software |
| technical points to consider before the | | | | RAID. Modern Linux distributions come with |
| machine is boxed, shipped and colocated.Make | | | | tools to administer and monitor the |
| sure the Operating System rebootsAll | | | | performance of software RAID arrays.It can be |
| colocated dedicated servers run "headless." | | | | helpful to duty technicians if all the main |
| This means without the use of a keyboard or | | | | power lights are working. The power light, |
| monitor attached. Therefore you will need to | | | | hard drive activity light and network light |
| ensure that the servers gets past the BIOS | | | | can be very useful. It goes without saying |
| screen and boots the desired kernel without | | | | that the server should be correctly labelled |
| having to press any keys. It might be | | | | at the front with it's hostname and IP |
| possible to set the BIOS on your dedicated | | | | address so it can be identified quickly.Paul |
| server to stop on "no errors."If your are | | | | Lee has over six years experience in the web |
| running Linux the kernel you will need to | | | | hosting industry and was formerly Senior |
| ensure the correct kernel is booted without | | | | System Administrator with Limited. He |
| intervention. This is usually determined by | | | | currently lives and works in London and runs |
| the configuration on /etc/grub.conf if the | | | | his own consultancy and hosting company |
| GRUB boot loader is used, or /etc/lilo.conf | | | | Weycrest. |
| if the LILO boot loader is used. After any | | | | |